a name that does not suit what it refers to, or the use of such a name

It was the scruffiest place I've ever stayed in, so "Grand Hotel" was a complete misnomer. 那是我住过的最不整洁的地方，叫它“尊贵酒店”有点取名不当。

It's something of a misnomer to refer to these inexperienced boys as soldiers. 用“军人”来指这些没有经验的男孩有些用词不当。